1. Field of the Invention
The present invention relates to a passive element chip and a manufacturing method thereof, and a highly integrated module and a manufacturing method thereof.
2. Description of the Related Art
To achieve a higher packaging density for electric equipment, there has been proposed a method for incorporating active elements, such as semiconductor chips, and passive elements, such as inductors, capacitors and resistors, in a substrate (self-contained substrate). The applications for such a self-contained substrate has been limited because it is difficult to guarantee that active elements or passive elements are nondefective once they are incorporated into a chip.
Patent Document 1, namely, Japanese Unexamined Patent Application Publication No. 2002-261449 (page 9, FIG. 1) has disclosed a self-contained module, which is fabricated by embedding a bare chip semiconductor device, inductors, capacitors and other passive elements in sheets made of a thermosetting resin and these sheets are bonded to form multi-layer laminate, and wiring patterns of the layers are electrically connected through inner via holes passing through the layers.
Patent Document 2, namely, Japanese Unexamined Patent Application Publication No. 2003-158214 (pages 3 to 6, FIGS. 1 and 2) has disclosed a wiring assembly (self-contained module) that has substantially the same shape as that of one surface of a semiconductor device. The wiring assembly includes a semiconductor element interface circuit. Inductors, capacitors, resistors and other passive elements required for the interface circuit are embedded in the wiring assembly. More specifically, a groove is formed in a surface of the semiconductor device, which is adjacent to a terminal, and a wiring pattern and passive elements, such as inductors, capacitors, and resistors, are placed in the groove.
In the self-contained modules disclosed in Patent Documents 1 and 2, the passive elements are included in a thermosetting resin or the like in the form of individual chip components. However, including individual chip components requires a large area for the chip components themselves and the wires extended among the chip components. As the number of passive elements increases, the completed module incorporating them will be undesirably large.
It could be possible to reduce the number of passive elements by building passive elements into a semiconductor chip in a semiconductor process. However, forming passive elements originally mounted in discrete form into a semiconductor chip would interfere with active elements, such as transistors and may adversely affect the characteristics of the active elements.